The invention is concerned specifically with cleaner heads which incorporate a motor-driven agitator. The vacuum cleaner, on the other hand, may be of any general type. For example, the cleaner head may be a fixed cleaner head on an upright vacuum cleaner, or alternatively it may be the cleaner head of a floor tool used with a cylinder vacuum cleaner or stick-vac cleaner.
It is conventional to provide the cleaner head of a vacuum cleaner with an agitator, such as a rotating brush bar, for agitating or “beating” a floor surface—particularly carpet—to improve pick-up performance.
Although the main vac-motor on the cleaner can be used to drive this agitator, it is more common to use a separate, dedicated motor to drive the agitator. This separate motor can then be positioned close to the agitator—usually somewhere on the cleaner head itself—to simplify the transmission arrangement. In a particularly space-efficient arrangement described in U.S. Pat. No. 1,914,834—FIG. 1 of which has been reproduced here—the cleaner head a has an agitator in the form of a hollow tubular brush bar d rotatably mounted on an axle b. This brush bar d effectively constitutes a rotor which is driven by an armature c housed inside the brush bar d.
It is preferable that the agitator in a cleaner head is separately removable for cleaning, repair or replacement. However, in the arrangement in U.S. Pat. No. 1,914,834 this is made impossible because the armature c prevents separate removal of the brush bar d.